Although a tan has long been considered a symbol indicative of good health and the ability to secure sufficient leisure time to enjoy many and numerous outdoor activities, it has become very evident that excessive exposure of the human skin to sunlight is harmful.
It is well documented that human skin and most likely most mammalian skin, is sensitive to sunlight and artificial light containing radiation of wavelengths between about 290 nanometers (nm) and 400 nm. Ultraviolet radiation of wavelengths between about 290 nm and 320 nm (UV-B region) has been known to rapidly produce damaging effects on the skin including reddening or erythema, edema, blistering or other skin eruptions in more severe cases. Prolonged or chronic exposure to radiation in this wavelength range has been associated with serious skin conditions such as actinic keratoses and carcinomas. In recent years, concern has also been expressed regarding ultraviolet radiation of wavelengths above 320 nm (UV-A region) and the adverse effects of such radiation on human skin. The radiation between 320 and 400 nm also contributes to the premature aging of the skin. In addition, recent studies indicate that chronic sun exposure limits the immunoresponse of the skin. There is some evidence that a tan will offer some protection against burning but that the tan is quite ineffectual against many other types of solar damage and there is no evidence that a tan increases immunoresponsive function in human skin.
Growing public awareness that the enjoyment of outdoor activities includes the need for adequate sun protection has led to an unprecedented growth in the area of sunscreen products. A very recent study by Margaret Schlumph from the Institute of Pharmacology and Toxicology at the University of Zurich, supports earlier health concerns regarding the use of endocrine disrupting organic substances in nearly all UV screening chemicals used in sunscreens. Additionally, the use of Aloe, or more specifically aloe barbadensis Miller has heretofore been known as a useful agent for the formulation of sunscreens as well as a substance that can both reduce UV damage to human skin that is inflamed and also promote healing. What was not well documented until recent publications and a subsequent U.S. Pat. No. 5,824,659 by Strickland and coworkers is that an extract found in all Aloe plants that is normally removed during carbon adsorptive processing, is capable of providing cyctoprotection to the mammalian skin. This extract boosts the immune system response of the skin, thereby significantly reducing the risk to various forms of skin cancer. There is strong evidence to suggest that this beneficial effect translates to skin in most mammals, thereby the present invention provides a possible preventative formulation for animals in zoos or other habitats where UV exposure could be hazardous to the animals' health.
It is therefore desirable to provide a UV protective product that has the following attributes: protection in both the UV-A and UV-B ultraviolet radiation ranges; maintenance of coverage, i.e., waterproof and perspiration proof; application and use convenience, i.e., ease of application, invisibility, non-staining and non-greasy; and freedom from irritation as a result of its ingredients, in particular, its active sunscreen ingredients should also be void of any known or suspected endocrine disrupters. Recent interest in this area includes some concerns over the irritancy and sensitization problems in addition to the endocrine disruptive nature that may occur in some individuals utilizing sunscreen products with high SPF values containing organic sunscreen agents. In addition, the UV protective product could also include known cytoprotective oligosaccharides from aloe barbadensis Miller preventing damage to the skin immune system caused by harmful UV radiation. “Cold-pressed” Aloe which contains the beneficial oligosaccharides and provides an emollient base for the UV protective formulation is possibly the best known choice as a cytoprotective agent that inhibits the loss of skin immunocompetency induced by ultraviolet radiation, as this agent is readily available and comparably inexpensive. Other such inhibitors are not yet well known but it is believed that amino-acids, vitamins or pro-vitamins, nucleo-derivatives, and vegetable extracts, wherein said amino-acids comprise tryptophan, histidine, phenylalanine, tyrosine, said vitamins and pro-vitamins comprise vitamin B6, vitamin A, vitamin E, tocopherols, betacarotene, bioflavonoids, nucleotides and polymers thereof, cascara, frangula, camomile, hyperic, calendula, elicriso, licorice or essential oils thereof all may have similar cytoprotective or immune boosting effects on mammalian skin.
One current measure of effectiveness of a sunscreen or sun-block product is indicated by its sun protection factor (SPF). The sun protection factor is the ratio of the amount of exposure (dose) required to produce a minimal erythema reaction in protected skin to the amount required to produce the same reaction in unprotected skin. The absolute dose differs for each human and for each mammal, and is largely dependent on genetic predisposition and ethnic origin of the human. If a human or other mammal would normally require ten-minute exposure to sunlight to develop a minimal erythema reaction, then using an SPF 15 sunscreen should allow for tolerance of up to 150 minutes of sunlight before developing a minimal erythema. Relatively recent public awareness of the problems of exposure to sunlight has led to a demand for sunscreen products with high SPF values, i.e., at or above SPF 8.
What has not been well considered in the sunscreen and cosmetics industry heretofore, is the possibility of enhancing the immuno-responsiveness of skin cells to UV light by the proper topical application such as described above by the use of extracts of aloe or similar naturally occurring substances. Such substances would preferably not be processed, but if the beneficial effects are not lost during processing, then either the processed or non-processed substance may be used.
A more complete rating mechanism than the SPF rating method is suggested here. The immuno-response rating system could be a simple 0-10 value, with 10 applying to a substance within the UV-protective composition that is most beneficial to boosting skin cell immune responsiveness to carcinoma, melanoma, etc. (for instance).
What has also not been well considered by the same industry is the effect that certain agents, recently determined to be endocrine disrupters, may have on certain mammals, particularly humans, regarding the immune system response to UV radiation. Endocrines are essentially excretions from organs or glands. The organs or glands continually function by discharging waste or at the least exchanging fluids from an inlet side to an outlet side. Any disruption in the natural behavior of an organ or gland could have a deleterious effect on the ability of that organ or gland to continue to function normally.
In a systems approach to health, the abnormal function of any organ or gland could lead to immune system disruptions (and immune system deficiencies) that may lead to serious health related complications. Changes in endocrine behavior has recently been linked to hormonal imbalances seen in young and especially adolescent or pubescent children, as well as in the global food chain where hermaphroditic insects and other animals have been discovered.
A UV-protective formulation or composition that may inhibit normal endocrine function(s) is at least undesirable, and at most a potential health threat to millions who continue to apply such a formulation or composition directly to their skin. Although the SPF value may be high, the potential for endocrine disruption may also be high and again this poses the possibility of another ranking system. In ranking potential endocrine disruption substances, again the 0-10 rating has appeal, with 0 being the desired criteria that a consumer would want to purchase to ensure consumption of a quality product that is also completely safe in terms of potential adverse health effects.
Therefore, as part of the present invention, a new rating system for UV-protective compositions is proposed that includes;    SPF value—greater than 15 desired    Immuno-responsiveness factor (IRF)-5 or higher desired (greater than 0)    Non-endocrine disrupter factor (NED)—0 desired
Therefore the ultimate UV-protective formulation would safely block or screen UV light, enhance the immune responsiveness of the skin in the absence or presence of UV, and ensure the user that there is no endocrine disrupting substance present.
Ease of application and cosmetic appeal, on the other hand, are important in formulating sunscreen compositions. These characteristics rely on subjective evaluations such as visual and tactile impression by the user. Consumer research studies indicate that a sunscreen or sun-block formulation should rub in easily, leave the skin non-sticky and, above all should be invisible on the skin after application. Sunscreen compositions containing organic sunscreen agents have been found, in some cases, to irritate the skin. Additionally, recent studies have confirmed the suspicion that endocrine disrupting agents exist in currently available sunscreen formulations including; benzophenone-s, homosalate, 4-methylbenzylidene camphor, octyl methoxycinnamate, and octyl-dimethyl-PABA. All of these substances, in fact, made cancer cells grow more rapidly and three caused developmental effects in animals. Therefore a non-endocrine disrupting UV protective formulation should include the use of inorganic sun-block agents, such as titanium dioxide and zinc oxide. In addition the need for an acceptable emollient that reduces the negative affects associated with abrasive inorganics and that also includes the benefit of providing cytoprotection and healing of the skin is necessary. Allowing for the reduction of irritation or sensitization of the skin suggests that “cold-pressed” Aloe is a useful and necessary ingredient for such a UV-protective formulation.
Our review of the prior art in this field includes the following pertinent information;
For example, Japanese Patent Application No. 1981-161, 881, describes cosmetics containing 0.140% of ultrafine divided titanium oxide with a particle size of 10-30 nm which has been rendered hydrophobic. It indicates that when hydrophobically treated titanium dioxide with a particle size of 10-30 nm is blended into cosmetic base materials, it transmits visible light but reflects and scatters the harmful ultraviolet rays. It has been found that when these titanium dioxide compositions are utilized as a sunscreen agent in sunscreen compositions, it may result in the loss of one of the most desired properties of such compositions, i.e., invisibility.
U.S. Pat. No. 5,028,417, issued Jul. 2, 1991, describes sunscreen compositions containing microfine titanium dioxide. The particle size of the titanium dioxide is required to be less than 10 nm. It also states that other sunscreen agent can be utilized with the titanium dioxide.
U.S. Pat. No. 5,340,567, issued Aug. 23, 1994 describes a sunscreen composition comprising a synergistic combination of titanium dioxide having a particle size of less than about 35 nm and zinc oxide having a particle size of less than about 50 nm with titanium dioxide and zinc oxide being present at given ratios.
German Patent No. 3642794(1987) describes a cosmetic composition for preventing sunburn which contains 1-25% zinc oxide of a particle size of 70-300 microns. It further indicates that the composition may also contain titanium dioxide of a particle size of 30-70 microns. This composition is undesirably due to its unaesthetic whiteness characteristics at high SPF levels.
U.S. Pat. No. 5,188,831, issued Feb. 23, 1993, describes sunscreen compositions wherein the sunscreen effect is obtained from a blended of oil-dispersible ultrafine titanium dioxide and water dispersible titanium dioxide. However, the SPF level obtained is only of 10 with a total concentration of titanium dioxide of 5.0% w/w.
World Patent Application WO 90/06103, published Jun. 14, 1990, describes titanium dioxide sunscreen where the microfine titanium dioxide particles are coated with a phospholipid, either through the use of a powder mill or through the making of a dispersion in an oil phase containing the phospholipid with a high shear mixer. The phospholipid coated titanium dioxide is the incorporated into sunscreen compositions. A high efficiency is claimed: the data presented shows SPF values of up to 11 for a 3.75% titanium dioxide concentration and up to 25 for a for a 7.5% concentration of titanium dioxide. The use of high shear mixer or a powder mill is complicated and energy intensive process.
EP 535372 A1, published Apr. 7, 1993 describes a method of preparing sunscreens in which a dispersion of zinc oxide and/or titanium dioxide particles in an oil are formed by milling.
EP 619999 A2, published Oct. 19, 1994 describes an aqueous dispersion of particulate metallic oxide of particle size less than 200 nm mixed with an emulsifier and an oil phase and also an organic hydrophobic sunscreen to form an o/w emulsion. The resulting sun protection composition has a higher SPF than would be expected if there was only an additive effect. However, the titanium dioxide alone at 4% yielded a SPF of only 7 to about 11.
EP 628303, published Oct. 19, 1994 describes a process for preparing a sunscreen composition. It consists of mixing sunscreen particles of metallic oxide less than 200 nm dispersed in an oil with one or more emulsifier and/or organic sunscreens. The resulting sunscreen composition is claimed to have a SPF value considerably higher than expected. The high SPF is only obtained when a metallic oxide is blended with an organic sunscreen. In fact, when no organic sunscreen is used, the SPF value is only about 7.
WO 93/11742 describes sunscreen compositions comprising titanium dioxide and iron oxide of particle size less than 200 nm preferably coated with a phospholipid.
An article published in DCI in September 1992 by Tioxide Specialties Ltd. Describes ways of incorporating oil or water dispersions of titanium dioxide in emulsions. However, no data is given on the resulting SPF values.
An article published in Cosmetics and Toiletries, Vol. 107, October 1992, describes various ways of formulating with a physical sunblock. The discussion focuses on using titanium dioxide in a dispersion or using an emulsifier which is also an effective dispersing agent for titanium dioxide. It states that SPF's far above 20 can be achieved. However, no examples are given, nor does the article mention the specific sunscreen components or their composition.
A brochure published by the Tioxide Company on Mar. 15, 1994, discloses inorganic sunscreens of high SPF values obtained without the addition of any organic sunscreens. When measured, the SPF of the sunscreen compositions was indeed that described. However, when the titanium dioxide concentration was measured, it was at least twice what was claimed.
U.S. Pat. No. 5,498,406 describes sunscreen compositions in an oil-in-water emulsion containing both organic and inorganic sunscreens and comprising long chain (C2545) alcohols for stabilization of the emulsion. This composition relies predominately on the organic sunscreen actives. While the authors mention the use of stearic acid as a part of the oil in water composition, they teach against the use of stearic acid in stabilizing the titanium dioxide with C 22-45 alcohols.
U.S. Pat. No. 6,099,825 describes sunscreen having disappearing color which is extremely useful when combined with titanium dioxide or zinc oxide. It was unexpectedly found that although the inclusion of particulate pigments in a sunscreen emulsion can render the sunscreen visually colored as it is being spread onto the skin and that the coloration will substantially disappear when the sunscreen emulsion is rubbed into the skin.
U.S. Pat. No. 6,042,813 also describes sunscreen having disappearing color indicator. The sunscreen includes at least one active sunscreen agent, at least one emulsifier, sufficient amounts of water to create the colored emulsion, and at least one oil-soluble dye that imparts color to the emulsion.
U.S. Pat. No. 6,048,517, issued Apr. 11, 2000, describes low-cost sunscreen compositions with high SPF values of at least 40. The ingredients in the sunscreen include mixtures of homosalate, octyl salicylate, oxybenzone, octyl methoxycinnamate, or avobenzone.
U.S. Pat. No. 5,770,183, issued Jun. 23, 1998, describes an emulsion that contains a water phase and an oil phase that includes active sunscreen ingredients and skin conditioning agents. The sunscreen provides an SPF greater than 30, and the particle size in the oil phase averages 2.0 Microns, providing high levels of protection from the sun while using minimum amounts of active sunscreen agents.
U.S. Pat. No. 5,492,690, issued Feb. 20, 1996, describes a method for preventing skin damage by applying a substance that includes a benzolyacetate ester and seems to describe a potential non-endocrine disrupting benzoylacetate ester that would require testing prior to use in the present inventive composition(s).
U.S. Pat. No. 5,747,010, issued May 5, 1998, describes means and methods of protecting skin from the oxidative effects of UVA radiation using a substance that contains a lipophilic anti-oxidant. Such an anti-oxidant, if proven to be non-endocrine disruptive and not to interfere with the cytoprotective qualities of the present inventive composition(s) could also be useful and beneficial.
WO 99/11236 published first in Germany and then as a WO document dated Mar. 11, 1999, describes a transparent sunscreen gel that contains methylvinyl ether and maleic acid copolymers cross-linked with decadiene.
EP 0834301, published Mar. 8, 1998, describes compositions that include glutathione liposomes combined with at least one emulsifier and are topically applied to the skin to prevent the damaging effects of UV radiation.
U.S. Pat. No. 5,914,102, issued Jun. 22, 1999, describes an oil-in-water sunscreen emulsion comprised of at least one ultraviolet-absorbing organic compound and hydrophobically-treated silica particles. The concentration of the organic compounds is at least 30 times the concentration of the silica.
U.S. Pat. No. 5,916,542, issued Jun. 29, 1999, describes a mixture comprised of natural substances that effectively protect against skin damage caused by UVA and UVB light.
U.S. Pat. No. 5,945,090, issued Aug. 31, 1999, describes a high-SPF sunscreen comprised of an algae extract, aloe vera, and tapioca powder that protects against UVA and UVB light.
U.S. Pat. No. 5,980,871, issued Nov. 9, 1999 to Johnson and Johnson, and apparently licensed to Neutrogena, describes a sunscreen composition that includes inorganic sunscreen agents, such as titanium dioxide or zinc oxide, anionic emulsifiers, and an oil component. The composition allows for SPF greater than 10 with a titanium dioxide concentration of about 4%. This U.S. Pat. No. 5,980,871 further describes the method required to make the sunscreen.
This patented composition and method most closely resembles the present invention. There is no mention, however, of the use of any cytoprotective agents or the importance of providing only non-endocrine disruptive agents to the composition. In our review of commercially available products, this composition would appear to pose the least risk in terms of both short and longer-term health effects. The product itself, however, is somewhat undesirable as it leaves a very white appearance on the skin for long periods of time, is difficult to spread, and somewhat abrasive to sensitive skin.
Thus, in one possible embodiment, the present invention is directed toward a colored sunscreen or sun-block emulsion comprising: (a) at least one ultramarine pigment that imparts a color other than white to the emulsion with a titanium dioxide or zinc oxide or possibly fumed or fused silica or even silicon dioxide so that when the emulsion is rubbed into the skin, the color substantially disappears; (b) at least one sunscreen or sun-block active agent in an amount effective to protect skin against the actinic radiation of the sun; (c) no known or suspected endocrine disrupting organic substances; (d) a cytoprotective substance such as a glucose-rich mannose-containing oligosaccharide obtained from and used with aloe barbadensis Miller as the at least one emulsifier; and (e) sufficient water to form the other than a white colored emulsion.
The amount of the ultramarine pigment in the composition can range form about 0.5 to about 10 weight percent of the composition, preferably form about 1 to about 5 weight percent of the final formulation.
Optionally, the colored sunscreen emulsion can contain one or more additional ingredients, including emollients, waterproofing agents, dry-feel modifiers, insect repellants, antimicrobial preservatives and/or fragrances.
In another embodiment, the present invention is directed towards a method for protecting the skin against sunburn while increasing mammalian skin cell immunoresponse to cancerous skin cells while eliminating possible endocrine disruption response of human organs comprising topically applying the sunscreen formulation as described above to the skin.
An advantage of the present invention is that it provides a sunscreen or sub-block and a method for protecting against sunburn that enables the user to apply the sunscreen more completely and uniformly to the skin, thus providing more effective protection against skin damage and homogenously enhancing cytoprotection while eliminating endocrine disruptive organics, thus providing for long term health and safety in the presence of UV light.
Another advantage of the present invention is that it provides a sunscreen or sun-block with a color indicator which has a low fabric staining potential, and for which those stains that form can easily be removed from fabrics.
Still yet another advantage of the present invention is that it provides an optionally colored sunscreen or sun-block and a method for protecting against sunburn that is more enjoyable for human use because of the attractiveness and appealing nature of the color indicator.
For domesticated animals, the use of matching colors may also be appealing.